For the second time in as many months, two planes near Houston's Bush Intercontinental Airport came close to colliding mid-air before air traffic controllers corrected their courses, averting potential disaster.

The most recent incident occurred Thursday just before 7 p.m. A Singapore Airlines 777, a jumbo jet, flew within 200 feet vertically and within about a half-mile horizontally of a Delta Airlines A320, according to officials. That's a separation of about eight football fields horizontally.

Federal Aviation Administration rules say that aircraft must remain separated a half-mile vertically and 3 miles horizontally. FAA officials are currently investigating the incident.

The planes were 10 miles northeast of the airport, according to the FAA's Lynn Lunsford.

"An air traffic controller noticed the deviation and issued traffic alerts and instructions to the pilots of both aircraft. The FAA is still determining the closest proximity between the two flights," said Lunsford Saturday.

"As a result of a preliminary analysis of the event, the FAA has taken steps to ensure that all flight crews are aware of the top altitudes for standard departure routes," he said.

In late May the FAA was investigating an incident where two passenger jets came close to a collision in the skies above Houston earlier that month on May 9. An air traffic controller's mistake put one aircraft directly in the path of another.

Live air traffic control reports for the May incident revealed the controller telling United Flight 601, which had just taken off, to turn right, putting it in the path of Flight 437. At the closest, the two airliners were about 0.87 miles apart with about 400 vertical feet separating them, officials said.